1. Field of the Invention
The present invention is directed to a frequency divider of the type employed in mobile telecommunication systems, and is directed particularly to a type of frequency divider known as a "dual modulus prescaler".
2. Description of the Prior Art
Frequency dividers of the type known as dual modulus prescalers are employed in frequency synthesizers of mobile telecommunication systems. Such frequency dividers have division factors switchable between 1/N and 1/(N+1), whereby N typically amounts to 64 or 128, and operate at frequencies on the order of magnitude of 1 GHz and are a component of every GSM or in DECT telephone. Since such telephones are usually batter-powered, the importance of low power consumption by all components, including the frequency divider, is significant.
Examples of the employment and the structure of such prescalers are known from the IEEE Journal of Solid-State Circuits, Vol. 29, No. 10, October, 1994, pages 1206 through 1211 as well as Vol. 27, No. 12, December, 1992, pages 1794 through 1798, wherein asynchronous divider expansion stages follow a respectively synchronous 1:4/5 divider.